Research On The Hardware Implementation Of The Visible Light Communication

Along with the great achievement research and manufacturing of LEDs technologies such as high power LEDs, high performance LEDs, the ideas of using Visible Light in communication also began to attract many researchers from the world in the recent years.Many results of researching on LED to meet the Visible Light Communication’s requirements has also made some great achievements, such as fast response LED, LED’s lighting characteristics, high power LEDs...The results of researching on photo-detector has also got many achievements, such as fast respond time photo-detector, high sensitive photo-detector...Currently, the RF electronic equipments used everywhere, however, electromagnetic waves are not allowed to use in some places as some special areas of some hospitals or on a plane...At these places, electromagnetic waves may have some negative effects, so that the electronic device that is used electromagnetic waves need to be turned off or temporary suspend their communication. But, visible light has some advantages compared to the RF devices, there are no interference or impact on human health, so, researching on using visible light for communication immediately attract the attention of many researchers.The our research team is mainly researching on MIMO algorithms; giving some solutions to reduce the power requirement of transmitter, increase the transmission distance, and increase the data speed. The main contributions of this thesis for the VLC project are:Based on the properties of light, give some solutions to help improve the efficiency of VLC, which is helping to reduce the loss of light energy on the transmission path, research on the reflection properties of the two types of mirror, which are hyperbolic mirror and parabolic mirror. Then, combine two parabolic and hyperbolic mirrors to create a Cassegrain mirror system(this idea comes from parabola antenna in RF system). This mirror system helps enhance the power of the light on the transmission line.Proposed some solutions to extend the working area of the LEDs, that is LED predistortion technique. Give some solutions for the LED power amplifier or LED driver circuit, which helps increase the capacity of the emitting light, which means reducing the BER factor in communication. Research on how to use bi-color LED type in VLC. With two separate independent colored LED, it can be used to transmit a digital signal, such as NRZ, Manchester, etc... One single color can be used as a pilot signal. Proposed several solutions for bi-color LED amplifier, and analyze the advantages and disadvantages those circuits.